Sci FQ #28 pg 53-54

1. In which state did the Three Mile Island accident occur? a. Pennsylvania b. Illinois c. California d. Ohio e. Florida

1. A-The Three Mile Island accident occurred on March 28, 1979 in Dauphin County, Pennsylvania. As a result, the United States cancelled many of its orders for nuclear power reactors. [53,2,2]

10. Which phrase BEST describes the negative health impacts from Fukushima Daiichi? a. relatively large b. relatively small c. disastrous d. too small to detect e. moderate

10. D-According to a 2013 study, the Fukushima Daiichi disaster resulted in extremely small negative health impacts among evacuees. Nevertheless, Japan shut

11. Which of the following problems BEST describes a nuclear meltdown? a. a fire at a nuclear power plant b. the decomposition of a plant's fuel rods c. an overheating of nuclear fuel d. an unintended nuclear bomb e. an explosion of nuclear material

11. C-Overheated nuclear fuel, rather than a major explosion, creates a nuclear meltdown. A nuclear power plant lacks enough uranium to generate such an explosion. [54,1,3]

12. Which of the following problems would MOST likely cause an explosion during a nuclear accident? a. insufficiently enriched uranium b. overheated nuclear fuel c. pressure buildup d. low levels of uranium-235 e. a nuclear meltdown

12. C-The uranium in a nuclear power plant simply cannot explode like a bomb because it is enriched below the weapons-grade enrichment level. Only pressure buildup or other system failures could cause explosions at the plants. [54,1,3]

13. Reactor-grade uranium would MOST likely be enriched a. 6% b. 90% c. 31% d. 3% e. 11%

13. D-Weapons-grade uranium is enriched 90%, while reactor-grade uranium is enriched between 2% and 4%. Reactor-grade uranium's low enrichment prevents bomb-like explosions at nuclear power plants. [54,1,3]

14. Which of the following statements is NOT true of nuclear weapons? a. They operate above criticality. b. Their energy output grows exponentially, until they run out of fuel. c. They release as much energy as possible as quickly as possible. d. They rely entirely on nuclear fission. e. They are designed to be similar to nuclear reactors.

14. E-Nuclear weapons are designed to expel high amounts of energy in very short periods of time. They do so with exponentially increasing output, making them different from nuclear reactors, which maintain constant power output. [54,1,4]

15. All of the following measurements could be comparable to the total energy produced by a fission bomb EXCEPT a. 1 ton of TNT b. 0.93 tons of TNT c. 500,000 tons of TNT d. 737,000 tons of TNT e. 435,000 tons of TNT

15. D-A fission bomb can produce energy ranging from just below one ton of TNT to 500,000 tons of TNT. Bombs like these can be weapons of mass destruction. [54,1,4]

16. Which of the following definitions BEST explains critical mass? a. the minimum amount of fissile material needed to create and maintain a nuclear chain reaction b. the maximum amount of fissile material an atomic bomb can have c. the amount of uranium needed to power a nuclear power plant d. the size fuel rods must be to effectively generate power at a nuclear power plant e. the mass of uranium required to make an atomic bomb

16. A-The critical mass is the minimum amount of fissile material needed for each fission event to cause at least one other fission event, effectively creating a nuclear chain reaction. This measurement is necessary for atomic bombs. [54,2,1]

17. Which fruit provides the BEST comparison for the critical mass of weapons-grade uranium-235? a. cantaloupe b. grapefruit c. apple d. watermelon e. orange 18. The two MAIN methods of achieving critical mass are the a. gun-type method and implosion method b. conventional method and explosion method c. sub-critical method and unconventional method d. critical method and safe method e. fission method and fusion method 19. Which radioactive element did the Nagasaki atomic bomb use? a. uranium b. plutonium c. radium d. einsteinium e. polonium 20. Which of the following explanations concerning critical mass is NOT true? a. The gun-type method fires two subcritical pieces together using conventional explosives. b. The implosion method increases the density of a subcritical mass above criticality. c. Critical mass is always achieved at the instant of detonation. d. Critical mass is essential in forming nuclear fusion bombs. e. The implosion method uses explosives to compress a subcritical mass inward

17. A-Weapons-grade uranium-235 has a critical mass of a sphere with a 6.8 inch diameter, roughly the size of a cantaloupe. [54,2,1]

18. The two MAIN methods of achieving critical mass are the a. gun-type method and implosion method b. conventional method and explosion method c. sub-critical method and unconventional method d. critical method and safe method e. fission method and fusion method

18. A-The gun-type method and the implosion method are the two main ways of reaching critical mass. The implosion method is more popular now than the gun-type method. [54,2,1]

19. Which radioactive element did the Nagasaki atomic bomb use? a. uranium b. plutonium c. radium d. einsteinium e. polonium

19. B-During World War II, the United States dropped a plutonium fission bomb on Nagasaki, Japan. Nuclear weapons typically use uranium-235 or plutonium-239. [55,1,1]

2. Which piece of the nuclear reactor at Three Mile Island triggered the disaster when it suddenly shut down? a. a generator b. a water pump c. the primary coolant loop d. a turbine e. the secondary coolant loop

2. B-A water pump at Three Mile Island suddenly shut down, stopping the circulation of the secondary coolant loop. This initial equipment failure ultimately led to the flooding of the containment structure. [53,2,2]

20. Which of the following explanations concerning critical mass is NOT true? a. The gun-type method fires two subcritical pieces together using conventional explosives. b. The implosion method increases the density of a subcritical mass above criticality. c. Critical mass is always achieved at the instant of detonation. d. Critical mass is essential in forming nuclear fusion bombs. e. The implosion method uses explosives to compress a subcritical mass inward.

20. D-Critical mass is essential in forming nuclear fission bombs, not fusion bombs. The two main methods of reaching critical mass - gun-type and implosion - both fire subcritical particles together at the instant of detonation. [55,2,1; 56,1,0]

3. Which of the following events during the Three Mile Island nuclear accident came FIRST? a. The secondary loop boiled off. b. Residual reactions continued to generate heat. c. Water flooded the containment structure. d. The primary loop increased in temperature and pressure. e. The reactor was turned off.

3. E-After a water pump failed, stopping the secondary coolant loop's circulation, the reactor was shut down quickly, but residual reactions continued, generating heat. These reactions caused the secondary loop to boil, leading to an increase in temperature and pressure in the primary loop, ultimately flooding the containment structure. [53,2,2]

4. Three Mile Island largely affected a. human health b. global climate change c. public opinion about nuclear power d. public perception of the government e. countries' relationships with the United States

4. C-Studies did not link the Three Mile Island accident to dangerous health impacts. The incident did, however, shift public opinion about nuclear power, halting its overall growth in the United States. [53,2,2]

5. Which nuclear disaster is generally considered the WORST in history? a. Sosnovy Bor b. Three Mile Island c. SL-1 d. Fukushima Daiichi e. Chernobyl

5. E-Many consider the Chernobyl accident to be the worst nuclear disaster in history. It occurred on April 26, 1986 when a reactor vessel exploded, releasing a cloud of radioactive gas. [54,1,1]

6. Which of the following errors BEST explains the origins of the Chernobyl accident? a. a water pump failure led to a flooded containment structure b. overheated fuel rods c. a flawed cooling system design d. an earthquake combined with a tsunami e. a flawed reactor combined with operating errors

6. E-The Chernobyl accident occurred as a result of a flaw in a reactor's design. When human operating error added to this problem, the reactor vessel exploded, releasing a cloud of radioactive gas. [54,1,2]

7. Which of the following statements does NOT describe the Chernobyl accident? a. The Chernobyl accident released 400 times less radioactive material than the bombing of Hiroshima. b. The Chernobyl accident increased concerns about nuclear power, even in the United States. c. Thirty-one people died as a result of the Chernobyl accident. d. Soviet and American reactor designs differed significantly, making the Chernobyl accident unlikely in the United States. e. Many people needed to be relocated away from the radioactive material from Chernobyl.

7. A-The Chernobyl accident released 400 times more radioactive material than the bombing of Hiroshima, Japan during World War II. It also killed thirty-one people and relocated hundreds of thousands of others. [54,1,1]

8. Which safety precaution was taken immediately after the earthquake that caused the Fukushima Daiichi? a. Everyone left the plant. b. Coolant was increased. c. Control rods were inserted into the coolant. d. Fuel rods were inserted into the coolant. e. Operators shut down the entire plant.

8. C-Directly after the earthquake of March 11, 2011, the control rods at the Fukushima Daiichi plant were inserted into the coolant. At the time, it was unknown that disaster loomed ahead, so workers remained at the plant and took safety precautions. [54,1,2]

9. Which action did Japan perform on all of its nuclear plants immediately after Fukushima? a. decommissioning them b. adding safety staff c. changing the type of fissile material d. temporarily shutting them down e. decreasing amounts of fissile material

9. D-After Fukushima Daiichi, Japan shut down the fifty-four nuclear power plants in the nation. The plants had to undergo safety assessments. [54,1,2]